Effect of Fingolimod on Platelet Count Among Multiple Sclerosis Patients

BACKGROUND: While many studies have previously focused on fingolimod's effect on immune cells, the effect it has on circulating and local central nervous system platelets (Plts) has not yet been investigated. This study will elucidate what effects fingolimod treatment has on multiple sclerosis (MS) patients’ plasma Plt levels. In addition, it will propose possible reasoning for these effects and suggest further investigation into this topic. METHODS: This quasi-experimental study used patients from the Isfahan Multiple Sclerosis Society to produce a subject pool of 80 patients, including 14 patients who ceased fingolimod use due to complications. The patients had their blood analyzed to determine Plt levels both 1-month prior to fingolimod treatment and 1-month after fingolimod treatment had been started. RESULTS: The mean level of Plts before initiation of fingolimod therapy (Plt1) among these MS patients was 256.53 ± 66.26. After 1-month of fingolimod treatment, the Plt level yielded an average of 229.96 ± 49.67 (Plt2). This number is significantly lower than the average Plt count before treatment (P < 0.01). CONCLUSIONS: MS patients taking oral fingolimod treatment may be at risk for side-effects caused by low Plt levels. This may not be a factor for patients with higher or normal Plt levels. However, a patient with naturally low Plt levels may experience a drop below the normal level and be at risk for excessive bleeding. In addition to these possible harmful side-effects, the decreased Plt population may pose positive effects for MS patients.